An efficient strategy overcoming the bottleneck in Candida parapsilosis catalyzing stereoinversion from (R)-1-phenyl-1, 2-ethanediol to the corresponding counterpart

作者：Hu, Qingsen; Xu, Yan^*; Nie, Yao

来源：Journal of Chemical Technology and Biotechnology, 2010, 85(2): 252-257.

DOI：10.1002/jctb.2296

• Candida parapsilosis
• stereoinversion
• extractive biocatalysis
• product inhibition
• coenzyme regeneration

BACKGROUND: Microbial stereoinversion has been widely used for the biosynthesis of numerous chiral compounds. However, little work has been done to improve the efficiency of microbial stereoinversion. This study investigated the bottleneck in the deracemization of 1-phenyl-1,2-ethanediol (PED), and then the efficiency and the sustainability of biocatalyst was improved significantly by using a strategy.
RESULTS: When (S)-PED concentration exceeded 17.5 g L-1, it strongly inhibited deracemization. Furthermore, the deficiency of NADPH regeneration also limited such reaction. To overcome these limitations, extractive biocatalysis was developed using adsorbent resin NKII combined with xylose addition for cofactor regeneration. Compared with the initial reaction condition, which only afforded (S)-PED with 35% optical purity after the first batch reaction at 30 g L-1 substrate concentration, the cells in the new system could be reused three times and the optical purity remained at a high level of 95%.
CONCLUSION: Product inhibition and coenzyme regeneration had a significant effect on catalytic activity of Candidaparapsilosis. By using a resin and D-xylose, the efficiency and reusability of whole-cell catalyst can be considerably improved, which would be helpful for effective synthesis of high value chiral intermediates.

• 出版日期2010-2
• 单位江南大学